London Underground drivers belonging to the Aslef union have voted for a 24-hour strike over the introduction of a new Night Tube service at weekends.
Aslef said 97.6 per cent of members had voted in favour of striking over the introduction of the new 24-hour service, due to be introduced in September this year.
The organisation - of which 80 per cent of London Underground drivers are members - added that "new rosters... mean Tube drivers will have to work an unlimited number of weekend and night shifts for no extra pay".
The 24-hour strike will take place from 9.30pm on 8 July, which the union said will shut down the "entire tube network". "More dates to be announced," it added.
Finn Brennan, Aslef's district organiser, said there was a "window of opportunity".
"[London Underground managers] need to withdraw the threat to impose new rosters and make a realistic offer on pay and conditions. We are always prepared to talk."
Steve Griffiths, London Underground's chief operating officer said it was "still in the midst of negotiations".
Other trade unions are also currently balloting for industrial action, with results due to be declared on 30 June.